"We have heard nothing for months and now they have given us the plaque back. We have been told we can't have permission.

"Their lives were not lost in an accident.

"This is something I would hope would never happen to anybody again."

The four brothers were killed by their farm labourer father on March 27, 2003.

He drove sons Joshua, seven, Thomas, six, Callum, five and Daniel, three, to the beauty spot during an access visit.

Young then gassed himself and the children by running a petrol lawnmower in the back of the family car.

As he did so, he rang Miss Tolley, who listened in horror as the boys succumbed to the carbon monoxide fumes.

Roslynne Lumsden, who runs the Horseshoe Pass Ponderosa Cafe gift shop, led the campaign to have the plaque erected. It is made from the same stone as the children's headstones.

Ms Lumsden said: "We were told we could have the plaque in the cafe car park. But the tragedy didn't happen here, it happened a quarter of a mile up the road.

"I was told it may 'open the floodgates' for others killed to have plaques along the roadside.

"But this is different. These children were killed by their father. They were not the victims of, say, a motorcycle accident.

"I just don't understand why they will not let her have the commemorative plaque there."

Llantsylio Community Council clerk Sandra Baker said: "We are incredibly sympathetic to Miss Tolley. It is absolutely devastating what happened.

"We have suggested that a commemorative seat be placed there.

"But we have been told locals don't want memorials there and we have been elected to represent local people."

But last night a ray of hope was offered to Miss Tolley.

The Countryside Council for Wales said if a planning application was made to Denbigh-shire County Council for the plaque to be erected, they would back it.

A Denbighshire council spokesman said: "The council was approached by the family, with a view to setting up a commemorative plaque on the Horseshoe Pass and the council has acted as a facilitator between the family and local individuals and organisations.

"We have advised the family that any plaque would need permission from the Countryside Council for Wales, as the site is located in a site of special scientific interest.

"The plaque would also need planning permission from the council and the matter would go through the normal planning process."